Karl Kästner, modified 2 Months ago.

Hej Igor,
This also affects Deflt3D-4/Dflow-FM. As suggested, this is due to an incompatibility of the source code with the GNU compiler 8, see https://gcc.gnu.org/onlinedocs/gfortran/Interoperable-Subroutines-and-Functions.html).
The simplest way is to work on an old system if available, such as Ubuntu 14 or 16, not 18.
Otherwise this tedious workaround for Delft3D on Ubuntu 18.10 might for you as well: